Mount Rushmore depicts, of course, the faces of four great US presidents – George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln – looming from a granite rock face set 5,725ft above sea level in the Black Hills of South Dakota. George Washington's face was completed in 1934, with Jefferson's following two years later. Abraham Lincoln, whose beard was a challenge, was next in 1937, with Teddy Roosevelt staring through granite glasses in 1939.

Source: BBC